Patients with clonal mast cell disease (CMD) such as systemic mastocytosis (SM) and Hymenoptera venom allergy (HVA) should receive immunotherapy for at least five years, according to a recently published study in The Journal of Allergy and Clinical Immunology: In Practice.
The term Hymenoptera comprises bees, ants, and wasps. Almost everyone has been bitten by one of these insects at least once. However, in some people, the venom from these insects can cause severe, life-threatening reactions.
“Between 7-26% of patients with HVA are estimated to have a clonal 135 MCD presenting as systemic mastocytosis or monoclonal mast cell activation syndrome (MMAS),” the authors wrote.
Having SM is a significant risk factor for suffering from a severe reaction to a Hymenoptera sting. The risk of anaphylaxis due to HVA is approximately 19% in patients with an MCD compared to 1% in the general population. In some cases, a severe HVA could be the first manifestation leading to an SM diagnosis.
Learn more about SM signs and symptoms
Patients who suffer a severe HVA should be screened for an MCD using a clinical and laboratory analysis known as the REMA score or examination of the skin in search of mastocytosis lesions. Tryptase genotyping and PCR assay are other options available if the attending physician considers the first two methods insufficient.
Patients with HVA and SM should receive preventive treatment to prevent life-threatening episodes. These patients should always carry epinephrine autoinjectors, which are available in case of a sting. In the author’s experience, patients with MCD usually require more than one injection to come out of a crisis.
Immunotherapy is the only effective preventive treatment for severe HVA. In patients with MCD and HVA continued immunotherapy for at least five years is recommended.
“Patients with clonal MCD have a high rate of anaphylaxis due to Hymenoptera envenomation. Often, anaphylactic reactions in these patients are rapid and severe,” the authors wrote. “Therefore, all patients with HVA should undergo screening for SM to determine the pretest probability of SM and whether a diagnostic bone marrow biopsy is warranted.”
